Snapdragons (Antirrhinum majus) are popular flowering plants known for their striking, tall flower spikes. They attract bees, but their pollination strategy is highly specialized, meaning they are not equally accessible to all bee species. The unique morphology of the snapdragon flower acts as a barrier, filtering out smaller insects. Only certain, powerful pollinators can access the nectar and pollen reward, demonstrating a specialized relationship between the plant and its insect visitor.
The Snapdragons’ Unique Pollination Mechanism
The common name “snapdragon” comes from the unique shape of the flower, which resembles a dragon’s mouth that opens and snaps shut. This distinctive structure is classified as zygomorphic, possessing bilateral symmetry. The flower is “closed,” composed of two main lips that must be physically separated to reveal the reproductive organs within.
The lower lip functions as a landing platform but is tightly pressed against the upper lip. Significant weight and force are required to push this lower petal down, opening the flower for entry. This mechanism limits access to the flower’s resources, ensuring pollen transfer only occurs via strong visitors.
The petal surfaces are covered in conical cells, which provide better friction for an insect to grip the surface. Experiments have shown that bees struggle on plants lacking these specialized cells, highlighting their role in facilitating the necessary leverage. This morphological specialization results in a highly efficient, targeted pollination system.
Primary Pollinators for Antirrhinum
The primary pollinator for the snapdragon is the bumblebee (Bombus). Bumblebees possess the body weight and muscle strength necessary to force open the tightly closed flower lips. As a bumblebee lands and pushes its way inside to reach the nectar, its back brushes against the anthers and stigma, resulting in effective pollen transfer.
This strong mutualism ensures that the plant’s resources are not wasted on smaller, less efficient floral visitors. In contrast, the common honeybee (Apis mellifera) is generally too lightweight to consistently force the flower open. Honeybees often struggle to access the interior legitimately, making them less efficient for the snapdragon’s reproduction.
Some bees may resort to “nectar robbing,” chewing a hole near the base of the flower’s corolla to steal the nectar reward. While this action provides the bee with food, it bypasses the stigma and anthers, offering no pollination service to the plant. The plant’s strict entrance mechanism favors the large, legitimate pollinator.
Maximizing Pollinator Activity in Your Garden
To increase legitimate bee visits to your Antirrhinum, plant them in large groupings, or “drifts.” Mass planting creates a highly visible target that is more attractive to foraging bees than scattered individual plants. Bumblebees are particularly drawn to flowers with specific color cues, such as magenta, red, or those featuring visible stripes or venation patterns that act as nectar guides, directing the bee to the entrance.
Consistent deadheading—the removal of spent flowers—is crucial. Deadheading prevents the plant from setting seed, diverting its energy instead into producing new blooms. This maintains a continuous food source for pollinators throughout the season. Placing snapdragons in a location that receives full sun promotes the vigorous growth and abundant flowering necessary to create a rich, long-lasting bee buffet.
Avoid using broad-spectrum pesticides, as these chemicals can harm the very bees you are trying to attract. Maintaining a chemical-free environment is paramount to supporting these beneficial insects. Focusing on these gardening practices creates the optimal conditions for the large, strong bees snapdragons depend on for successful reproduction.